Nanopesticide risk assessment based on microbiome profiling - Community structure and functional potential as biomarkers in captan@ZnO35-45 nm and captan@SiO220-30 nm treated orchard soil

Functional gene array and non-target soil microorganisms in nanopesticides captan@ZnO35-45nm and captan@SiO2 20-30nm environmental risk assessment

Currently there are no widely recognized standards for assessing the environmental risk of nanopesticides. Therefore, whether they are safer than conventional pesticide products remains open to discussion. We used non-target soil microorganisms as indicators of environmental change and applied functional gene arrays (FGAs) using GeoChip 5.0S targeting 151 000 genes involved in ecologically relevant functions. We synthesized nanofungicides in which the active substance captan was bound to inorganic nanocarriers (ZnO and SiO2) to examine the functional capabilities of microbial communities. During a 100-day microcosm study, changes in soil were compared to the effect of pesticide and nanocarriers alone. Based on 72 functional gene diversity profiles, we conducted environmental risk assessment of nanopesticides. Nanoagrochemicals affected the alpha and beta diversity of microbial functional genes, and the most profound negative effect was detected for captan, impacting carbon cycling and the organic remediation process from day 30. Additionally, the effect of nanopesticides changed during the experiment. On day 42, the effect was nanocarrier-dependent, and an increase of genes involved in denitrification (nirS, norB), archaeal conversion of N2 to NH3 and fungal N-assimilation was observed, especially for SiO2-treated set-ups. After 100 days, the negative effect was mainly related to the active substance released from the nanocarrier impacting the nitrate reductase gene (narG) and genes from the denitrification and nitrogen fixation subcategory. Analysis of microarrays did not indicate a recovery process for carbon cycling. Moreover, pesticide and nanoagrochemicals affected arsenic detoxification (aoxB, arsM, arsC), which may lead to an elevation of toxic As(III) availability. Our study indicated that FGAs are a sensitive method, revealing long-term changes previously undetected by other methods, including next-generation sequencing (NGS). This is the first study to confirm the usefulness of GeoChips for the evaluation of microbial redundancy as an important factor for fair environmental risk assessment of nanopesticides.

Nano-Formulated Pyraclostrobin With Iron Bismuthide Enhances Efficient Utilization of Active Ingredient and Improves Biosafety

The widespread application of pyraclostrobin (PYR), an important strobilurin fungicide with low utilization efficiency, urgently requires optimization for sustainable agriculture. In this study, nanoformulated PYR with nano-iron bismuthide (FeBi) was successfully prepared via flash nanoprecipitation, yielding spherical PYR/FeBi nanoparticles (NPs, Φ120 nm) with stable drug loading capacity (67.9%) and controlled release. These NPs exhibited enhanced anti-Botrytis activity in vitro and superior in vivo performance. On tomato leaves, PYR/FeBi NPs at 80 µg/mL achieved greater than 90% curative and protective efficacy against Botrytis cinerea infection and significantly mitigated lesion expansion, surpassing commercial PYR suspension concentrate (SC) at equivalent concentrations. On tomato seedlings, PYR/FeBi NPs significantly reduced gray mold disease by 89%, compared to 67% with PYR SC at the same concentration. The mechanism underlying this enhanced activity involved stronger disruption of mitochondrial metabolism, including acetylation process, oxalate production, and damage to mycelia and conidia. Further, PYR/FeBi NPs displayed reduced cytotoxicity on human Hek293 and Chinese hamster V79 cells compared to PYR SC. The results highlighted the biocompatibility and potential of PYR/FeBi NPs for efficient utilization of active ingredients in sustainable agriculture.

A review of the impact of herbicides and insecticides on the microbial communities

Enhancing crop yield to accommodate the ever-increasing world population has become critical, and diminishing arable land has pressured current agricultural practices. Intensive farming methods have been using more pesticides and insecticides (biocides), culminating in soil deposition, negatively impacting the microbiome. Hence, a deeper understanding of the interaction and impact of pesticides and insecticides on microbial communities is required for the scientific community. This review highlights the recent findings concerning the possible impacts of biocides on various soil microorganisms and their diversity. This review's bibliometric analysis emphasised the recent developments' statistics based on the Scopus document search. Pesticides and insecticides are reported to degrade microbes' structure, cellular processes, and distinct biochemical reactions at cellular and biochemical levels. Several biocides disrupt the relationship between plants and their microbial symbionts, hindering beneficial biological activities that are widely discussed. Most microbial target sites of or receptors are biomolecules, and biocides bind with the receptor through a ligand-based mechanism. The biomarker action mechanism in response to biocides relies on activating the receptor site by specific biochemical interactions. The production of electrophilic or nucleophilic species, free radicals, and redox-reactive agents are the significant factors of biocide's metabolic reaction. Most studies considered for the review reported the negative impact of biocides on the soil microbial community; hence, technological development is required regarding eco-friendly pesticide and insecticide, which has less or no impact on the soil microbial community.